JPH11260518A - Manufacture of anisotropic conductive sheet and its manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of the insulation failure of a conductive part, reduce the conduction resistance of the conductive part, and manufacture an anisotropic conductive sheet of a large area without using a large-size magnet. SOLUTION: One pair of metal molds 18 loaded on a belt conveyer 14 pass through a gap part 13 formed by the linear electromagnet pole 12a of a linear electromagnet 10a and the linear electromagnet pole 12b of a linear electromagnet 10b. By applying magnetic force to the pair of metal molds 18 through the linear electromagnet 10a and the linear electromagnet 10b at a passing time, nickel particles in the molding space are localized in a magnetic substance area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electric circuit component,
The present invention relates to a method for manufacturing an anisotropic conductive sheet electrically connected to terminals of an electric circuit board or the like and an apparatus for manufacturing the same.

[0002]

BACKGROUND ART FIGS. 23A and 23B are perspective views of an anisotropic conductive sheet, and FIG. 24 is a view taken along line AA of the anisotropic conductive sheet shown in FIG. It is sectional drawing which cut | disconnected. The anisotropic conductive sheet will be described with reference to FIGS. 23 (a), 23 (b) and 24. Anisotropic conductive sheet 120
Is an insulating sheet 122 made of, for example, silicone rubber.
In addition, a conductive portion 124 formed by laminating conductive magnetic particles such as nickel particles is locally formed. Examples of uses of the anisotropic conductive sheet include the following uses. When inspecting the electrical characteristics of semiconductor products that use solder balls as electrodes, if the probe for inspection is brought into direct contact with the solder balls, the solder balls will be chipped or dented, causing mounting problems There are cases. Therefore, by using an anisotropic conductive sheet instead of the probe to make contact with the solder ball, damage or deformation of the electrode is prevented.

A conventional method for manufacturing an anisotropic conductive sheet will be described with reference to FIG. On the main surface of the mold 126, the mold magnetic pole portions 136 and the non-magnetic material portions 138 are provided alternately, and similarly on the main surface of the mold 128, the mold magnetic pole portions 13 are provided.
7 and non-magnetic portions 139 are provided alternately. The molds 126 and 128 are arranged so that the main surface of the mold 126 and the main surface of the mold 128 face each other, and a spacer 134 is arranged around the molds 126 to form a molding space 140. For example, a molding material in which nickel particles are dispersed in liquid silicone rubber is put into the molding space 140. Then, the flat electromagnet 13 is sandwiched between the molds 126 and 128.
0 and 132 are arranged, and a magnetic field is applied to the molding space 140 so that the nickel particles 142 cause the mold magnetic pole portion 136 and the mold magnetic pole portion 13
7, the nickel particles 142 are localized, and the molding material is heated and cured in that state to produce an anisotropic conductive sheet. This manufacturing technique is disclosed in
It is disclosed in 146873.

[0004]

The conventional anisotropic conductive sheet manufacturing apparatus has two problems. First, the first problem will be described. Referring to FIG. 25, nickel particles 142 in the molding material are combined with mold magnetic pole 136 and mold magnetic pole 137.
And the degree of localization between the magnetic poles 136 and 132, the strength of the magnetic field generated by the electromagnets 130 and 132,
7 and is proportional to the product of the magnetic field gradient and the magnitude of the magnetic field gradient formed between them. The generated magnetic field here refers to a magnetic field for magnetizing the nickel particles 142, and the magnetic field gradient refers to a gradient for applying a force to the nickel particles 142 and moving the nickel particles 142. When the ratio of the gap g between the mold magnetic pole part 136 and the mold magnetic pole part 137 to the pitch p of the mold magnetic pole parts 136 and 137 is large, for example, larger than 1, the value of the magnetic field gradient localizes the nickel particles 142. Therefore, the nickel particles 142 cannot be sufficiently localized. When the anisotropic conductive sheet is manufactured by heating and curing the molding material in such a state, insulation failure between conductive portions of the anisotropic conductive sheet occurs. This will be described with reference to FIGS. FIG. 26 is a partial plan view of an anisotropic conductive sheet in which insulation failure has occurred between conductive portions. FIG.
FIG. 4 is a partial cross-sectional view taken along line -A. If the localization of the nickel particles 142 cannot be satisfactorily performed, the insulating sheet 122 between the conductive portion 124a and the conductive portion 124b may not be formed.
Since an anisotropic conductive sheet in which a large number of nickel particles 142 are present is formed, the conduction path is narrowed and the conduction resistance of the conduction portion is increased. In addition, since the anisotropic conductive sheet is pressed on both sides during use, such an anisotropic conductive sheet electrically connects the conductive portion 124a and the conductive portion 124b, and the conductive portion 124a Insulation failure occurs between the conductive portion 124b.

Here, the relationship between the ratio of the gap g between the mold magnetic pole portions to the pitch p of the mold magnetic pole portions and the magnitude of the magnetic field gradient will be described in detail. FIG. 28 shows a pair of molds 126, 1 using the flat electromagnets 130, 132 shown in FIG.
FIG. 4 is a partial cross-sectional view of a state in which a magnetic force is applied to 28. Magnetic force lines 144 are formed from the electromagnet 130 to the electromagnet 132. For the pitch p of the mold magnetic pole parts 136 and 137, the width w of the mold magnetic pole parts 136 and 137 is p / 2, and the height h of the mold magnetic pole parts 136 and 137 is p / 4. . Assuming that the maximum magnetic field intensity generated by the electromagnets 130 and 132 is 0.5 T, in the center between the mold magnetic poles,
The magnetic flux density B (T) in the x-axis direction is represented by g = p, g = 2
It measured about each case of p and g = 3p. The result is the graph of FIG. The magnetic field gradient dB / dx (T / m) obtained by differentiating the magnetic flux density B (T) with x is the graph of FIG. Note that x = 0, p, 2p... 5p correspond to the center of each mold magnetic pole. As shown in FIG.
= 2p, g = 3p, the magnetic field gradient becomes extremely low, which causes a problem in localization of nickel particles.

The second problem will be described. If the area of the surface of the flat magnet facing the main surface of the mold is smaller than the area of the main surface of the mold, the magnetic field does not act evenly on the mold and the nickel particles are localized. Cause problems. Therefore,
The area of the plate-type magnet must be equal to or greater than the area of the main surface of the mold. When the area of the anisotropic conductive sheet increases, the area of the flat-plate type magnet must be correspondingly increased. Therefore, when producing an anisotropic conductive sheet having a large area, the area is increased while maintaining the magnetic field strength, and a large magnet is required. Large magnets are expensive, increasing the cost of producing anisotropically conductive sheets.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to prevent the occurrence of insulation failure of a conductive portion and reduce the conductive resistance of the conductive portion. Another object of the present invention is to provide a method and apparatus for manufacturing an anisotropic conductive sheet that can produce a large-area anisotropic conductive sheet without using a large magnet.

[0008]

An apparatus for manufacturing an anisotropic conductive sheet according to the present invention applies a magnetic force to a molding space in which a molding material in which conductive magnetic particles are dispersed in a flowable curable material is arranged. This is an apparatus for localizing the conductive magnetic particles and thereafter curing the curable material to produce an anisotropic conductive sheet, comprising a pair of molds, a moving unit and a magnetic force line generating unit. .

The pair of molds has a nonmagnetic material region and a plurality of magnetic material regions functioning as magnetic poles on its main surface, and are arranged to face each other, so that the magnetic material region and the nonmagnetic material region are arranged. A molding space is formed by the main surface including. The moving means moves the mold relatively. The magnetic force line generating means generates magnetic force lines in the thickness direction of the relatively moved mold, and applies a magnetic force to the molding space when the mold passes through the space through which the magnetic force lines pass, thereby forming a conductive magnetic material. The apparatus for producing an anisotropic conductive sheet according to the present invention, in which particles are localized between magnetic material regions, comprises applying a magnetic force to a molding space when a mold passes through a space through which magnetic lines of force pass, whereby the conductive magnetic particles are Are localized between the magnetic regions. In other words, instead of applying a magnetic force to the entire main surface of the mold at once, a magnetic force is first applied to a part of the main surface, then the other part, and then another part, and the main part of the mold Magnetic force is applied to the entire surface. Therefore, even if the area of the surface of the magnet facing the main surface of the mold is smaller than the area of the main surface of the mold, the magnet force can be evenly applied to the mold. Therefore, according to the apparatus for manufacturing an anisotropic conductive sheet according to the present invention, a linear magnet can be used instead of a flat magnet.
Since the magnetic field gradient and the magnetic field strength of the linear magnet are larger than those of the flat-plate type magnet, the conductive magnetic particles are well localized between the magnetic regions even when g> p described above. Therefore, occurrence of insulation failure between the conductive portions can be prevented, and the conductive resistance of the conductive portion can be reduced.

The reason why the magnetic field gradient and the magnetic field strength of the linear magnet are larger than those of the flat magnet will be described in detail.

(1) Magnetic Field Gradient Conventionally, a magnetic force has been applied to a mold by a plate-shaped magnet. Since a plurality of magnetic material regions are scattered in the non-magnetic material region on the main surface of the mold, a non-uniform magnetic field is generated in the magnetic material region by this magnetic force, and the conductive magnetic field is generated by a magnetic field gradient caused by the non-uniform magnetic field. The body particles were localized between the magnetic regions. A flat magnet has a uniform magnetic field,
No magnetic field gradient is generated from the plate-type magnet itself. On the other hand, since the magnetic field of the linear magnet is not uniform, a magnetic field gradient is also generated from the linear magnet itself, and a synergistic effect of the magnetic field gradient by the magnetic material region itself of the mold and the magnetic field gradient by the linear magnet itself. The magnetic field gradient becomes larger than before.

(2) Magnetic Field Strength Since the magnetic pole of the linear magnet is linear, it is hardly affected by a demagnetizing field. Therefore, to easily saturate the conductive magnetic particles and the mold magnetic region,
The magnetic field strength increases.

Further, the apparatus for manufacturing an anisotropic conductive sheet according to the present invention does not apply a magnetic force to the entire main surface of the mold at one time as described above, but first applies a magnetic force to a portion of the main surface. In addition, a magnetic force is applied to the entire main surface of the mold by the operation of another portion, and then another portion. Therefore, even if it is a linear magnet, an anisotropic conductive sheet with a large area can be manufactured. Linear magnets are small and inexpensive. Therefore, the manufacturing cost of the anisotropic conductive sheet can be reduced. As a moving means, for example, using a belt conveyor, if the mold is placed on the belt conveyor and passed through the gap, it is possible to continuously apply a magnetic force to a large number of molds, and an anisotropic conductive sheet Can be produced in large quantities.

The line of magnetic force generating means includes a first magnet including a first magnetic pole portion, a second magnetic pole portion, and a gap formed by the first magnetic pole portion and the second magnetic pole portion. And a second magnet disposed on the mold, and when the mold passes through the gap by the moving means, a magnetic force is applied to the molding space to localize the conductive magnetic particles between the magnetic regions. Means are preferred. As the arrangement of the magnetic material regions, an arrangement in which a plurality of magnetic material regions are scattered in the non-magnetic material region on the main surface of the mold is preferable.

As an example of the linear magnet, there is a magnet in which the length of the side of the magnet in the same direction as the direction of movement is smaller than the length of the side of the mold in the same direction as the direction of movement. As another example of the linear magnet, the ratio of the width of the first and second magnetic pole portions to the distance between the first magnetic pole portion and the second magnetic pole portion is larger than 0 and smaller than 5, preferably There are magnets greater than 0 and less than 1. The height of the first magnet is preferably equal to or greater than the width of the first magnetic pole portion, and the height of the second magnet is preferably equal to or greater than the width of the second magnetic pole portion. One example of a curable material is a thermosetting resin. When a thermosetting resin is used as the curable material, it is preferable to further include a heating unit that heats and cures the curable material. First and second
The relative movement of the mold with respect to the magnet may mean that the magnet is fixed and the mold is moved, the mold is fixed and the magnet is moved, or both the mold and the magnet are moved. . The first and second magnets include, for example, electromagnets and permanent magnets.

The method for producing an anisotropic conductive sheet according to the present invention is characterized in that a magnetic force is applied to a molding space in which a molding material in which conductive magnetic particles are dispersed in a flowable curable material is applied. A method for producing an anisotropic conductive sheet by localizing body particles and then curing a curable material, wherein the molding space is moved relative to a space where a magnetic force is present, The magnetic particles are localized. Therefore, it is possible to prevent the occurrence of insulation failure of the conductive portion, reduce the conductive resistance of the conductive portion, and produce an anisotropic conductive sheet having a large area without using a large magnet. The reason is the same as in the case of the apparatus for manufacturing an anisotropic conductive sheet according to the present invention.

The molding material that can be used in the present invention has such an extent that the conductive magnetic particles can assemble into the mold poles when a magnetic field is applied during the production of the conductive magnetic particles and the anisotropic conductive sheet. It is made of an electrically insulating polymer material that has fluidity and then hardens. The conductive magnetic particles have ferromagnetism as particles and have conductivity at least on the surface. That is, it may be a single ferromagnetic metal or a composite particle, that is, a mixture particle, or a coated particle made of an organic or inorganic material coated with a metal. As such conductive magnetic particles, for example, nickel, iron, particles of a ferromagnetic metal such as cobalt or particles of an alloy containing them, or these particles, gold, silver, copper, tin, palladium, Rhodium or the like coated by plating or the like, non-magnetic metal particles or inorganic particles or polymer particles such as glass beads, plated with a conductive ferromagnetic metal such as iron, nickel, and cobalt, and the like can be given. . From the viewpoint of reducing the manufacturing cost, in particular, nickel, iron, or particles of these alloys are preferable, and gold-plated for applications such as sockets and connectors that utilize the electrical characteristics of low conduction resistance. Particles can be preferably used. Further, as the conductive magnetic particles, whiskers (whiskers) such as iron, and short-fiber ferromagnetic metals are also used.

As the polymer material, silicone rubber, ethylene propylene rubber, urethane rubber, fluorine rubber, polyester rubber, styrene butadiene rubber, styrene butadiene block copolymer rubber, styrene isopropylene block copolymer can be used. There are polymer rubber and soft epoxy resin. These must be liquid or fluid at the temperature at the time of production of the anisotropic conductive sheet. Preferably, it is a liquid at room temperature, such as a thermosetting silicone rubber, and is cured by heating to form a solid rubber. What is fluid at the time of sheet production even when it is solid at room temperature and becomes solid after the production of the anisotropic conductive sheet, for example, a soft liquid epoxy resin, a thermoplastic elastomer, a thermoplastic soft resin, or the like is also used. After the production of the anisotropic conductive sheet, those having a crosslinked structure are preferable in terms of heat resistance, durability and the like.

These are solid in an anisotropic conductive sheet state, but preferably have rubber elasticity.
Depending on the use of the anisotropic conductive sheet, the sheet may have low elasticity. Further, depending on the use of the anisotropic conductive sheet, a material having adhesiveness or tackiness may be used. These polymer materials are not limited to the above-described examples, and are conventionally known to be used as an anisotropic conductive sheet, or materials having functions equivalent to or similar to the above materials. If there is, it is not particularly limited.

The anisotropically conductive sheet manufacturing method and the anisotropically conductive sheet manufactured by the manufacturing apparatus according to the present invention are mainly intended for those which are manufactured as a stand-alone product and handled independently. . However, the anisotropic conductive sheet manufactured according to the present invention is, for example, as described in JP-A-4-151889.
The anisotropic conductive sheet according to the present invention can be easily applied to a circuit board device including a circuit board and an anisotropic conductive connector layer integrally formed on a surface of a lead electrode region of the circuit board. The manufacturing method can also be easily applied to the method for manufacturing a circuit board device described in the publication.

[0021]

FIG. 1 is a schematic view showing the principle structure of an embodiment of the apparatus for manufacturing an anisotropic conductive sheet according to the present invention. A pair of dies 18 are mounted on the belt conveyor 14 which is an example of the moving means. Belt conveyor 1
Above 4, a pressure rotator 16 is arranged. By sandwiching a pair of molds 18 between the pressure rotator 16 and the belt conveyor 14 and rotating each in the direction of the arrow,
The pair of dies 18 are sent out in the direction of arrow A. Pressurizing rotor 16
When the pair of molds 18 are sandwiched between the belt conveyor 14, the belt conveyor 14 also presses the pair of molds 18 and plays a role of stabilizing the molding space. A pair of molds 18 sent in the direction of arrow A
Is first sent to the place where the linear electromagnets 10a and 10b are arranged. The linear electromagnet 10a has a linear electromagnet pole 12a at its tip. The linear electromagnet 10a is an example of a first magnet including a first magnetic pole portion. Linear electromagnet 10
Similarly, b has a linear electromagnet pole 12b at its tip. The linear electromagnet 10b is an example of a second magnet. The linear electromagnet 10a is arranged to face the linear electromagnet 10b, and a gap 13 is formed by the linear electromagnet pole 12a and the linear electromagnet pole 12b. The linear electromagnets 10a and 10b are arranged so that the belt conveyor 14 passes through the gap 13. 21a and 21b indicate the sides of the linear electromagnet poles 12a and 12b, respectively, in the same direction as the direction in which the mold 18 moves. And 19
Is the mold 18 in the same direction as the movement of the mold 18.
Are shown. The length of the side indicated by 12a and 12b is smaller than the length of the side indicated by 19.

When a pair of dies 18 placed on the belt conveyor 14 pass through the gap 13, magnetic force is applied by the linear electromagnets 10a and 10b, and the conductive magnetic particles are localized between the magnetic regions. Let me do. Linear electromagnet pole 12
Since the lengths of the sides indicated by 21a and 21b of a and 12b are smaller than the lengths of the sides indicated by 19 of the pair of molds 18, a magnetic force is applied to a portion of the main surface of the pair of molds 18 and then the other. The magnetic force is applied to the entire main surfaces of the pair of dies 18 by the operation of the portion of FIG.

After passing through the gap 13, the pair of dies 18 is sent to the place where the curing heater 20 is arranged. In a state where the conductive magnetic particles are localized between the magnetic regions,
The curable material is heated and cured by the curing heater 20,
The anisotropic conductive sheet is completed.

Another embodiment of the apparatus for manufacturing an anisotropic conductive sheet according to the present invention will be described with reference to FIG. FIG. 2 is a schematic diagram showing the principle structure of another embodiment of the present invention. FIG.
The same reference numerals are given to the same parts as those of the production apparatus for anisotropically conductive sheets shown by the symbols, and the description thereof is omitted. The linear electromagnet 10 a is arranged inside the cylindrical surface of the nonmagnetic drum 22. The non-magnetic drum 22 rotates in the direction of the arrow with the inner peripheral surface of the cylinder of the non-magnetic drum 22 in contact with the linear electromagnet pole 12a. A pair of molds 18
When there is nothing between the pair of molds 18 and the linear electromagnet poles 12a when passing through the gap 13, the pair of molds 18 may stick to the linear electromagnet poles 12a. Therefore, the nonmagnetic drum 22 presses the pair of dies 18 to maintain the molding space and prevents the pair of dies 18 from sticking to the linear electromagnet poles 12a. The pair of molds 18 that have passed through the gap 13 are hardened by heaters 20 a and 20.
b is sent to the place where it was located. Curing heater 20a
Is arranged to face the curing heater 20b, and a pair of dies 18 on the belt conveyor 14 pass through the space. The curing heater 20a includes a small electromagnet 2
4a and 26a are provided at intervals. Similarly, the curing heater 20b is provided with small electromagnets 24a and 26b at intervals. Linear electromagnets 10a and 10
b causes the conductive magnetic particles to be localized between the magnetic regions, and in that state, the curing heaters 20 a and 20
b is sent to the place where it is arranged, and the curable material is cured by heating. However, even when the curable material is heated and cured by the curing heaters 20a and 20b, the cured conductive material is not immediately cured, so that the localized conductive magnetic particles may be dispersed again, and the small electromagnets 24a, 24b, 26a And 26b,
At the time of heat curing, a magnetic force is again applied to the pair of dies 18 to prevent the conductive magnetic particles from being dispersed. A plate 28 is provided between the pressure rotators 16, and the plate 28 presses the pair of dies 18 and plays a role of stabilizing the molding space.

FIG. 3 is a schematic diagram showing the principle structure of still another embodiment of the apparatus for manufacturing an anisotropic conductive sheet according to the present invention. Although the anisotropic conductive sheet manufacturing apparatus shown in FIGS. 1 and 2 moves the pair of dies 18 to pass through the gap, in this embodiment, the magnet is moved to move the pair of dies 18. The mold passes through the gap. This will be described in detail with reference to FIG. A pair of molds 18a, 18b, 18c,
18d are placed on the mold supporting sheet 44 at intervals. The rail 3 is located above the mold support sheet 44.
8a, and a rail 38b is provided below. A linear electromagnet 40a that is moved in the direction of arrow A is disposed on the rail 38a.
A linear electromagnet 40b that is moved in the direction of arrow A is arranged. The gap 4 is defined by the linear electromagnet pole 48a of the linear electromagnet 40a and the linear electromagnet pole 48b of the linear electromagnet 40b.
6 are formed. The linear electromagnets 40a and 40b are indicated by arrows A
When moved in the direction, the gap 46 is
Through 18d in order.

A curing heater 42a is disposed on the rail 38a, and the curing heater 42a is similarly disposed on the rail 38b.
b is arranged. The curing heaters 42a and 42b move in the direction of arrow A. After the conductive magnetic particles are localized between the magnetic regions by the linear electromagnets 40a and 40b, the curable material is heated and cured by the curing heaters 42a and 42b to complete the anisotropic conductive sheet.

Next, the fact that the linear electromagnet has a larger magnetic field gradient than the flat electromagnet will be described with reference to FIG. FIG. 4 is a partial cross-sectional view showing a state where a magnetic force is applied to a pair of molds using a linear electromagnet. The linear electromagnet poles 12a and the linear electromagnet poles 12b of the linear electromagnet are arranged with a gap G therebetween. Linear electromagnet poles 12a and 12
The width W of b is G / 2. Magnetic force lines 36 are formed from the linear electromagnet pole 12a to the linear electromagnet pole 12b. A pair of molds 18a and 18b pass through a gap formed by the linear electromagnet pole 12a and the linear electromagnet pole 12b. The main surface of the mold 18a has a mold magnetic pole 30
a and the nonmagnetic portion 32a are provided alternately, and the mold magnetic pole portion 30b and the nonmagnetic portion 32b are provided alternately on the main surface of the mold 18b. The mold 1 is placed such that the main surface of the mold 18a faces the main surface of the mold 18b.
8a and 18b are arranged, whereby the molding space 34 is formed. The molding space 34 contains a molding material in which nickel particles are dispersed in liquid silicone rubber. Liquid silicone rubber is an example of a curable material that can flow under molding conditions, and nickel particles are an example of conductive magnetic particles. The gap between the mold 18a and the mold 18b is g. The pitch of the mold magnetic pole portions 30a and 30b is p. The width w of the mold magnetic pole portions 30a, 30b is p / 2, and the height h of the mold magnetic pole portions 30a, 30b is p / 4. Assuming that the maximum magnetic field strength generated at the center of the linear electromagnet magnetic poles 12a and 12b is 0.5T, X
The magnetic flux density B (T) in the axial direction is represented by g = p, g = 2
It measured about each case of p and g = 3p. The result is the graph of FIG. The magnetic field gradient dB / dx (T / m) obtained by differentiating the magnetic flux density B (T) with X is the graph of FIG. Note that x = 0, p..5p corresponds to the center of each mold magnetic pole.

First, referring to FIG. 5 and FIG. 29, the maximum value of the magnetic flux density between the magnetic poles of the mold is 0.58T for both the flat magnet and the linear magnet. Since the density rapidly attenuates in the width direction, the attenuation width from the maximum value of the magnetic flux density is large. As a result, with reference to FIGS. 6 and 30, the maximum value of the magnetic field gradient is determined by using a linear magnet. Is larger than when a flat magnet is used. As shown in FIG. 6, even when g = 2p, the absolute value of the magnetic field gradient is about 250 (T / m), and the nickel particles can be localized. On the other hand, in the conventional plate-type electromagnet, as shown in FIG. 30, when g = 2p, the magnetic field gradient becomes extremely low, which causes a problem in localization of nickel particles.

Next, it will be described that when the same amount of exciting current is applied to the electromagnet, the magnetic field strength of the linear magnet is larger than that of the flat magnet. Referring to FIG. 7, linear electromagnets 10a and 10b are arranged such that a gap is formed between linear electromagnet pole 12a and linear electromagnet pole 12b. The distance between the linear electromagnet pole 12a and the linear electromagnet pole 12b is G. The width W of the linear electromagnet poles 12a, 12b is 2G. Reference numeral 36 denotes a line of magnetic force.

Referring to FIG. 8, flat-plate-type electromagnets 130 and 130 are formed such that a gap is formed between magnetic pole 131a of flat-type electromagnet 130 and magnetic pole 131b of flat-type electromagnet 132.
132 are arranged. Magnetic pole 131a and magnetic pole 131b
Is G as in the case of the linear electromagnet shown in FIG. The width W of the magnetic poles 131a and 131b is 20d which is ten times the linear electromagnet magnetic poles 12a and 12b in FIG. Reference numeral 144 denotes a magnetic field line.

At the center between the magnetic poles, the magnetic flux density B (T) in the x-axis direction was measured for each of the electromagnets shown in FIGS. The value of the exciting current is the same. Note that x = 0 corresponds to the center of the magnetic pole. The results are shown in the graph of FIG. Even when the distance between the magnetic poles and the exciting current are the same, the linear magnet has a higher magnetic flux density than the flat-plate type magnet. An increase in magnetic flux density means an increase in magnetic field strength.

Next, the shape of the linear magnet that can be used in the present invention will be described. FIG. 10 is a schematic diagram of an example of a linear electromagnet that can be used in the present invention. Since it has the same structure as the linear electromagnets 10a and 10b shown in FIG.
The description of the structure is omitted. H indicates the magnetic pole length, G indicates the distance between the magnetic poles, and W indicates the magnetic pole width. FIG. 11 is a cross-sectional view of the linear electromagnets 10a and 10b shown in FIG. Linear electromagnet 10a and linear electromagnet 10b
Thus, an H-shaped space is formed.
A gap 13 is formed between the linear electromagnet pole 12a and the linear electromagnet pole 12b.

FIG. 12 is a schematic view of another example of the linear electromagnet which can be used in the present invention. Linear electromagnet 50a
Are the linear electromagnet magnetic poles 52a, 52b, 52c, 5
2d, and the magnetic poles of the linear electromagnet 50b are also branched to linear electromagnet magnetic poles 54a, 54b, 54c, and 54d. Between the linear electromagnet poles 52a and 52b, between 52b and 52c, and between 52c and 52d,
Each pressurizing rotor 16 is arranged. The distance D between adjacent magnetic poles is preferably equal to or greater than the magnetic pole width W. This is because if the distance D between the adjacent magnetic poles is equal to or less than the magnetic pole width W, the sharpness of the magnetic field distribution between the magnetic poles decreases, and the magnetic field gradient decreases. FIG. 13 is an enlarged view of the magnetic pole portion of the linear electromagnet shown in FIG. The magnetic flux density generated at the center between the magnetic poles is represented by a graph in FIG. Note that x = 0, p, 2p, 3p
Corresponds to the center of each magnetic pole. Referring to FIG.
The peak of the magnetic flux density occurs at a position corresponding to the center of each magnetic pole. The value of the magnetic flux density is the same as that of the linear electromagnet shown in FIG. However, when the linear electromagnet has four pairs of magnetic poles as shown in FIG.
Occurs in some places. Therefore, the pair of dies 18 pass through four locations where the magnetic flux density peaks, so that the localization of the conductive magnetic particles can be ensured as compared with the case where the pair passes through one location.

FIG. 15 is a schematic view of still another example of the linear magnet that can be used in the present invention. Linear electromagnet 5
The magnetic pole 6a is branched into linear electromagnet magnetic poles 58a and 58b. Similarly, the magnetic pole of the linear electromagnet 56b branches into the linear electromagnet magnetic poles 60a and 60b. The difference from the linear electromagnets described so far is that the linear electromagnet poles 58
a is an N pole, and a linear electromagnet pole 60a facing the N pole
Is the south pole. The linear electromagnet pole 58b is an S pole, and the opposing linear electromagnet pole 60b is an N pole. FIG. 16 is an enlarged view of the magnetic pole portion of the linear electromagnet shown in FIG. The magnetic flux density generated at the center between the linear electromagnet 56a and the linear electromagnet 56b is shown in the graph of FIG. The way of setting the x-axis is the same as in FIGS. 13 and 14, and the description is omitted. The value of the magnetic flux density is the same as in the case of the linear electromagnet shown in FIG. 1, but peaks of the magnetic flux density are generated at two places, and one is positive and the other is negative. Since the magnetic flux density peaks occur at two locations, the localization of the conductive magnetic particles can be performed more reliably than when the peaks occur at one location. In addition, since the peak of the magnetic flux density having the opposite sign is generated, the once magnetized particles retain the residual magnetization even when the external magnetic field (the magnetic field from the electromagnet) is cut off. And the directions of the south poles are almost aligned with the previous external magnetic field direction. By applying a magnetic field in the opposite direction, the magnetic moment receives a torque. That is, the particles move slightly due to the rotating force. The force that brings particles and localizes them to the conductive part is the same as other linear magnetic poles, but the particles move by reversing the direction of the magnetic field, and the particles localized in the conductive part are rearranged. Since a dense conductive portion can be formed, it contributes to a reduction in conduction resistance.

FIG. 18 is a schematic view of still another example of the linear electromagnet which can be used in the present invention. The linear electromagnets 62a and 62b are arranged such that a gap is formed between the linear electromagnet pole 64a of the linear electromagnet 62a and the linear electromagnet pole 64b of the linear electromagnet 62b. The surface of the linear electromagnet magnetic pole 64a is recessed in a semi-cylindrical shape, and a cylindrical pressure rotor 66 made of a magnetic material is rotatably disposed in that portion. The pressurizing rotator 66 functions to send out a pair of dies in the direction of the arrow A similarly to the other pressurizing rotators 16 and also serves as a magnetic pole of the linear electromagnet 62a.
The effect of the linear electromagnet shown in FIG. 18 is almost the same as that of the linear electromagnet shown in FIG. That is, the shape of the tip of the linear electromagnet pole may be flat, as described above, or may be cylindrical, as in this example.
It means there is no limit.

FIG. 19 is a schematic view of still another example of the linear electromagnet usable in the present invention. The linear electromagnet 6 is arranged such that the linear electromagnet pole 70 of the linear electromagnet 68a and the linear electromagnet pole of the linear electromagnet 68b form a gap.
8a and 68b are arranged. On the surface of the linear electromagnet pole 70, a pressure rotor 7 made of a magnetic material is provided at intervals.
4a, 74b, 74c and 74d are rotatably arranged. The pressure rotors 74a, 74b, 74c, 74d are:
In addition to playing a role similar to that of a normal pressure rotor, it also plays a role of a magnetic pole of the linear electromagnet 68a. That is, the magnetic pole of the linear electromagnet 68a is divided into four and has the same structure as having four magnetic poles. The linear electromagnet 68b branches into four linear electromagnet magnetic poles 72a, 72b, 72c, 72d. The effect of the linear electromagnet shown in FIG.
This is almost the same as the effect of the linear electromagnet indicated by.

(Example) Next, an example of the present invention will be described.

The diameter of the conductive magnetic particles is about 0.1.
An anisotropic conductive sheet having a length of 400 mm, a width of 400 mm, and a thickness of 0.5 mm in which cylindrical conductive portions of 25 mmφ were arranged in a square lattice at a pitch of 0.25 mm was produced.

First, a mold was manufactured as follows.
Referring to FIG. 20, the diameter d (width w) is about 0.125 mmφ in a region of 400 mm in length and 400 mm in width on one side of each of two iron plates 80 a and 80 b having a length of 420 mm, a width of 420 mm, and a thickness of t6 mm. A columnar nickel magnetic pole 75 having a height h of 0.1 mm is formed by electrolytic plating in a square lattice shape with a pitch p of 0.25 mm, and the magnetic pole peripheral portion is made of epoxy resin so that the magnetic pole surface side of the mold becomes flat. To form a non-magnetic material portion 82 to produce a pair of molds 76a and 76b.

Also, the thickness is 0.5 mm, the outer shape is 420 mm,
One square frame made of nonmagnetic stainless steel having an inner shape of 400 mm was sandwiched between a pair of molds 76a and 76b to serve as a spacer for forming a molding space 84 for an anisotropic conductive sheet. The two dies 76a and 76b and the spacer have a diameter of 4 m for the alignment pin in order to perform accurate alignment between them.
Holes of mφ were prepared at four corners.

The two molds 76 thus produced are
An anisotropic conductive sheet was formed using the spacers a and 76b and the spacer. 10 particles of nickel, which are conductive magnetic particles, which are obtained by plating a thermosetting silicone rubber with gold having an average particle diameter of 20 μm,
The mixture was mixed at a ratio of volume% and uniformly dispersed to prepare a flowable molding material, which was filled in a molding space between a pair of molds formed by the spacers. The pair of molds filled with the molding material is placed on the belt conveyor 14 of the apparatus for manufacturing an anisotropic conductive sheet shown in FIG. 1, and the distance between magnetic poles (G in FIG. 10) 14
mm, the magnetic pole width (W in FIG. 10) is 14 mm, and the magnetic pole length (H in FIG. 10) is 450 mm, and generates a magnetic field 1T that substantially saturates the nickel magnetic poles of the molds 76a and 76b and the nickel particles in the molding material. Linear electromagnet poles 12a, 12b
At a constant speed of 100 mm / min.
After passing through a curing heater 20 set at 20 degrees and taking out and cooling, the molds 76a and 76b were opened to obtain an anisotropic conductive sheet. FIG. 21A is a schematic view of a micrograph of a partial cross section of the anisotropic conductive sheet.

(Comparative Example) Since the conventional apparatus does not have a large electromagnet corresponding to the size of the large mold used in the embodiment, the height and width of the mold of the comparative example are larger than those of the mold of the embodiment. The small size was 300 mm long and 300 mm wide. And the size of the electromagnet pole is 350m
An existing large electromagnet measuring 350 m in width and 350 mm in width was used.
Using this electromagnet and a mold, an anisotropic conductive sheet for comparison was produced. First, a mold was manufactured as follows in the same manner as in the example. 300mm long, 300mm wide, 6m thick
280m in length on one side of each of the two iron plates
m, 280 mm in width, a columnar nickel magnetic pole with a diameter of about 0.125 mmφ and a height of 0.1 mm is formed by electroplating in a square grid at a pitch of 0.25 mm. The non-magnetic portion was formed by filling the surface so that the surface was flat, and a pair of molds was manufactured. In addition, thickness 0.5mm, outer shape 300mm, inner shape 300mm
A non-magnetic stainless steel square frame was sandwiched between a pair of molds to form a spacer for forming a space for forming an anisotropic conductive sheet. Holes with a diameter of 4 mmφ for alignment pins were prepared at the four corners of the two mold substrates and the spacer in order to perform accurate alignment between them.

An anisotropic conductive sheet was formed by using the two dies and spacers thus manufactured. A thermosetting silicone rubber is mixed with gold-plated conductive ferromagnetic nickel particles having an average particle diameter of 20 μm at a ratio of 10% by volume, uniformly dispersed, and a fluid molding material is prepared. The molding space between the molds was filled. The mold filled with the molding material is sandwiched between the magnetic poles of the electromagnets 130 and 132 that generate 1T shown in FIG. 25, left for a sufficient time of 2 hours, taken out, and removed with a heater maintained at about 120 degrees. After heating for 30 minutes and cooling, the mold was opened to obtain an anisotropic conductive sheet. FIG. 21B is a schematic diagram of a micrograph of a partial cross section of the anisotropic conductive sheet. The anisotropic conductive sheet produced in the embodiment of the present invention shown in FIG. 21A has a conductive portion 87a with the nickel particles 88 well localized.
87b had been formed. 86 is a silicone rubber. On the other hand, in the anisotropic conductive sheet produced in the comparative example shown in FIG. 21B, the conducting portions 94a and 94b were formed in a state where the nickel particles 92 were not sufficiently localized. That is, a large number of nickel particles 93 existed between the conduction portion 94a and the conduction portion 94b.

Next, the average value of the conduction resistance to the strain in the thickness direction of each conductive portion of the anisotropic conductive sheet obtained in the example and that of the comparative example are shown in the graph of FIG. The average value of the conduction resistance with respect to the strain in the thickness direction of each conductive portion of the anisotropic conductive sheet obtained in the example was lower than that of the comparative example.

[0045]

[Brief description of the drawings]

FIG. 1 is a schematic view of one embodiment of an apparatus for producing an anisotropic conductive sheet according to the present invention.

FIG. 2 is a schematic view of another embodiment of the apparatus for manufacturing an anisotropic conductive sheet according to the present invention.

FIG. 3 is a schematic view of still another embodiment of the apparatus for producing an anisotropic conductive sheet according to the present invention.

FIG. 4 is a partial cross-sectional view showing a state where a magnetic force is applied to a pair of molds using a linear electromagnet.

5 is a graph in which the magnetic flux density B (T) in the x-axis direction is measured at the center between the mold magnetic pole portions of the mold shown in FIG.

6 is a graph showing a magnetic field gradient dB / dx (T / m) obtained by differentiating the magnetic flux density B (T) of the graph shown in FIG. 5 with x.

FIG. 7 is a schematic view of an example of a linear electromagnet.

FIG. 8 is a schematic diagram of an electromagnet used for comparison with the linear electromagnet shown in FIG. 7;

9 is a graph showing measured magnetic flux densities B (T) of the linear electromagnet shown in FIG. 7 and the electromagnet shown in FIG. 8 in the x-axis direction.

FIG. 10 is a schematic view of an example of a linear electromagnet that can be used in the apparatus for manufacturing an anisotropic conductive sheet according to the present invention.

11 is a sectional view of the linear electromagnet shown in FIG. 10 taken along line AA.

FIG. 12 is a schematic view of another example of a linear electromagnet that can be used in the apparatus for manufacturing an anisotropic conductive sheet according to the present invention.

FIG. 13 is an enlarged view of a magnetic pole portion of the linear electromagnet shown in FIG.

14 is a graph showing a measurement of a magnetic flux density B (T) in the x-axis direction of the linear electromagnet shown in FIG.

FIG. 15 is a schematic view of still another example of the linear electromagnet that can be used in the apparatus for manufacturing an anisotropic conductive sheet according to the present invention.

FIG. 16 is an enlarged view of a magnetic pole portion of the linear electromagnet shown in FIG.

17 is a graph showing a measurement of a magnetic flux density B (T) in the x-axis direction of the linear electromagnet shown in FIG.

FIG. 18 is a schematic view of still another example of the linear electromagnet that can be used in the apparatus for manufacturing an anisotropic conductive sheet according to the present invention.

FIG. 19 is a schematic view of still another example of a linear electromagnet that can be used in the apparatus for manufacturing an anisotropic conductive sheet according to the present invention.

FIG. 20 is a partial sectional view of a pair of molds used in the embodiment of the present invention.

FIG. 21 (a) is a schematic view of a micrograph of a partial cross section of an anisotropic conductive sheet produced in an example of the present invention,
(B) is a schematic diagram of a micrograph of a partial cross section of the anisotropic conductive sheet produced in the comparative example.

FIG. 22 is a graph showing the average value of the conduction resistance with respect to the strain in the thickness direction of each conductive portion of the anisotropic conductive sheet obtained in the example and that of the comparative example.

FIG. 23 (a) is a perspective view of an example of an anisotropic conductive sheet, and FIG. 23 (b) is a perspective view of another example of an anisotropic conductive sheet.

FIG. 24 is a cross-sectional view of the anisotropic conductive sheet shown in FIG.
It is sectional drawing cut | disconnected along the A line.

FIG. 25 is a view showing a state where a pair of molds is placed between electromagnets used in a conventional apparatus for manufacturing an anisotropic conductive sheet.

FIG. 26 is a partial plan view of an anisotropic conductive sheet in which insulation failure has occurred between conductive portions.

27 is a partial cross-sectional view of the anisotropic conductive sheet shown in FIG. 26, taken along line AA.

FIG. 28 is a partial cross-sectional view showing a state where a magnetic force is applied to a pair of molds using a flat-type electromagnet.

29 is a graph showing a measurement of a magnetic flux density B (T) in the x-axis direction at the center between the mold magnetic pole portions of the mold shown in FIG. 28.

FIG. 30 shows the magnetic flux density B (T) of the graph shown in FIG.
It is a graph which shows the magnetic field gradient dB / dx (T / m) differentiated by x.

[Explanation of symbols]

10a, 10b, 40a, 40b, 50a, 50b, 5
6a, 56b, 62a, 62b, 68a, 68b Linear electromagnets 12a, 12b, 48a, 48b, 52a, 52b, 5
2c, 52d, 54a, 54b, 54c, 54d, 58
a, 58b, 60a, 60b, 64a, 64b, 70,
72a, 72b, 72c, 72d Linear electromagnet magnetic pole 13, 46 Gap 14 Belt conveyor 18 A pair of molds 30a, 30b Mold magnetic poles 32a, 32b, 82 Non-magnetic material part 34, 84 Molding space 38a, 38b Rail 75 Nickel magnetic pole 76a, 76b Mold 86, 90 Silicone rubber 88, 92, 93 Nickel particles 87a, 87b, 94a, 94b Conducting part

Claims (7)

[Claims] A magnetic force is applied to a molding space in which a molding material in which conductive magnetic particles are dispersed in a flowable curable material is arranged to localize the conductive magnetic particles. An apparatus for producing an anisotropic conductive sheet by curing a curable material, comprising a non-magnetic material region and a plurality of magnetic material regions functioning as magnetic poles on its main surface, and arranged to face each other. Accordingly, a pair of molds in which the molding space is formed by the main surface including the magnetic region and the non-magnetic region, and a moving unit that relatively moves the mold, The magnetic force lines are generated in the thickness direction of the mold, and the space through which the magnetic force lines pass, by applying the magnetic force to the molding space when the mold passes,
Magnetic field lines generating means for localizing the conductive magnetic particles between the magnetic regions, and an anisotropic conductive sheet manufacturing apparatus. 2. The magnetic field generating device according to claim 1, wherein the magnetic field line generating means includes a first magnet including a first magnetic pole portion, and a second magnetic pole portion, and the first magnetic pole portion and the second magnetic pole. And a second magnet arranged so that a gap is formed by the part, and the moving means causes the mold to pass through the gap,
An anisotropic conductive sheet manufacturing apparatus, wherein the conductive magnetic particles are localized between the magnetic regions by applying the magnetic force to the molding space when the mold passes. 3. The apparatus for manufacturing an anisotropic conductive sheet according to claim 1, wherein the plurality of magnetic regions are scattered in the nonmagnetic region on the main surface of the mold. 4. The mold according to claim 1, 2 or 3, wherein a length of a side of the first and second magnetic pole portions in the same direction as the moving direction is equal to a length of the mold in the same direction as the moving direction. An anisotropic conductive sheet manufacturing device that is smaller than the side length. 5. The ratio of the width of the first and second magnetic poles to the distance between the first magnetic pole and the second magnetic pole according to claim 1, 2, or 3, An apparatus for producing an anisotropic conductive sheet that is large and smaller than 5. 6. The anisotropic material according to claim 1, wherein the curable material includes a thermosetting resin, and further includes heating means for heating and curing the curable material. Equipment for manufacturing conductive sheets. 7. A method for applying a magnetic force to a molding space in which a molding material in which conductive magnetic particles are dispersed in a flowable curable material, thereby localizing the conductive magnetic particles, and thereafter, A method for producing an anisotropic conductive sheet by curing a curable material, wherein the conductive magnetic particles are moved while relatively moving the molding space with respect to a space where the magnetic force is present. A method for producing an anisotropic conductive sheet, characterized by localizing.